Issue 3697 - Fall back to i18n.getUILanguage if @ui_locale isn't supported

lib/utils.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
- * Copyright (C) 2006-2016 Eyeo GmbH
+ * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-var Utils = exports.Utils = {
+"use strict";
+
+let Utils = exports.Utils = {
   systemPrincipal: null,
-  getString: function(id)
+  getString(id)
   {
-    if (typeof ext !== "undefined" && "i18n" in ext)
-      return ext.i18n.getMessage("global_" + id);
-    else
-      return id;
+    return ext.i18n.getMessage("global_" + id);
   },
-  runAsync: function(callback)
+  runAsync(callback)
   {
     if (document.readyState == "loading")
     {
       // Make sure to not run asynchronous actions before all
       // scripts loaded. This caused issues on Opera in the past.
-      let onDOMContentLoaded = function()
+      let onDOMContentLoaded = () =>
       {
         document.removeEventListener("DOMContentLoaded", onDOMContentLoaded);
         callback();
       };
       document.addEventListener("DOMContentLoaded", onDOMContentLoaded);
     }
     else
     {
       setTimeout(callback, 0);
     }
   },
   get appLocale()
   {
-    var locale = ext.i18n.getMessage("@@ui_locale");
-    if (locale === "") {

[Sebastian Noack, 2016/03/14 09:03:06]

Nit: We always use == (instead ===) where possible. This is inline with
Mozilla's JavaScript coding style.

-        locale = ext.i18n.getUILanguage();
-    }
-    locale = locale.replace(/_/g, "-");
+    let locale = ext.i18n.getUILanguage();
     Object.defineProperty(this, "appLocale", {value: locale, enumerable: true});
     return this.appLocale;
   },
   get readingDirection()
   {
-      var direction;
-      if ("chromeRegistry" in this) {
-        direction = this.chromeRegistry.isLocaleRTL("adblockplus") ? "rtl" : "ltr";

[Sebastian Noack, 2016/03/14 09:03:07]

This code path is specific to Adblock Plus for Firefox. The code here however is
only used on Chrome, Opera, Safari and Edge. So you can remove this branch.
However, you have to add Utils.readingDirection to the lib/utils.js in Adblock
Plus for Firefox as well.

-      }
-      else {      
-        var direction = ext.i18n.getMessage("@bidi_dir");
-        if (direction === "") {
-            direction = /^(ar|fa|he|ug|ur)(_|$)/.test(appLocale) ? "rtl" : "ltr";

[Sebastian Noack, 2016/03/14 09:03:07]

This logic is redundant with code in safari/ext/common.js which can be removed
now.

-        }
-      }
-      Object.defineProperty(this, "readingDirection", {value: direction, enumerable: true});
-      return this.readingDirection;
+    let direction = ext.i18n.getMessage("@@bidi_dir");
+    // This fallback is only necessary for Microsoft Edge
+    if (!direction)
+      direction = /^(?:ar|fa|he|ug|ur)\b/.test(this.appLocale) ? "rtl" : "ltr";
+    Object.defineProperty(
+      this,
+      "readingDirection",
+      {value: direction, enumerable: true}
+    );
+    return this.readingDirection;
   },
-  generateChecksum: function(lines)
+  generateChecksum(lines)
   {
     // We cannot calculate MD5 checksums yet :-(
     return null;
   },
-  makeURI: function(url)
-  {
-    return Services.io.newURI(url);
-  },
-
-  checkLocalePrefixMatch: function(prefixes)
+  checkLocalePrefixMatch(prefixes)
   {
     if (!prefixes)
       return null;
 
-    var list = prefixes.split(",");
-    for (var i = 0; i < list.length; i++)
-      if (new RegExp("^" + list[i] + "\\b").test(this.appLocale))
-        return list[i];
+    for (let prefix of prefixes.split(","))
+    {
+      if (new RegExp("^" + prefix + "\\b").test(this.appLocale))
+        return prefix;
+    }
 
     return null;
   },
 
-  chooseFilterSubscription: function(subscriptions)
+  chooseFilterSubscription(subscriptions)
   {
-    var selectedItem = null;
-    var selectedPrefix = null;
-    var matchCount = 0;
-    for (var i = 0; i < subscriptions.length; i++)
+    let selectedItem = null;
+    let selectedPrefix = null;
+    let matchCount = 0;
+    for (let subscription of subscriptions)
     {
-      var subscription = subscriptions[i];
       if (!selectedItem)
         selectedItem = subscription;
 
-      var prefix = require("utils").Utils.checkLocalePrefixMatch(subscription.getAttribute("prefixes"));
+      let prefix = Utils.checkLocalePrefixMatch(
+        subscription.getAttribute("prefixes")
+      );
       if (prefix)
       {
         if (!selectedPrefix || selectedPrefix.length < prefix.length)
         {
           selectedItem = subscription;
           selectedPrefix = prefix;
           matchCount = 1;
         }
         else if (selectedPrefix && selectedPrefix.length == prefix.length)
         {
           matchCount++;
 
           // If multiple items have a matching prefix of the same length:
           // Select one of the items randomly, probability should be the same
           // for all items. So we replace the previous match here with
           // probability 1/N (N being the number of matches).
           if (Math.random() * matchCount < 1)
           {
             selectedItem = subscription;
             selectedPrefix = prefix;
           }
         }
       }
     }
     return selectedItem;
   },
 
-  getDocLink: function(linkID)
+  getDocLink(linkID)
   {
-    var Prefs = require("prefs").Prefs;
-    var docLink = Prefs.documentation_link;
-    return docLink.replace(/%LINK%/g, linkID).replace(/%LANG%/g, Utils.appLocale);
+    let docLink = require("prefs").Prefs.documentation_link;
+    return docLink.replace(/%LINK%/g, linkID)
+                  .replace(/%LANG%/g, Utils.appLocale);
   },
 
-  yield: function()
+  yield()
   {
   }
 };